Avocados contain a toxic substance known as persin. Most parts of the avocado plant including the leaves, stems, fruits and pits may contain persin and damage the muscle of the heart and even your cat’s mammary glands. Symptoms of persin toxicity include congestion, vomiting, diarrhea, gastrointestinal distress, respiratory distress, possible fluid accumulation around the heart, and death. The meat and oils of specific kinds of avocados however do not prove to be toxic or harmful. If you’re going to give your pets avocados it’s best to leave it to the types that are in pet food as they’ve been removed of all toxic elements and are in small quanities:http://www.avodermnatural.com/About/avocados_bad_discussion.htm

Chocolate/Caffeine – Theobromine and caffeine are the ingredients in chocolate that contribute to the side effect in pets. The combination of these two ingredients can cause problems like vomiting and diarrhea, or severe and potentially fatal effects like heart arrhythmias or cardiac and respiratory arrest. It’s advised that the darker the chocolate is, the more harmful it is to pets. Cocoa powder and baker’s chocolate are the most dangerous, milk and white chocolate have the least amount of theobromine, and dark chocolate and semi-sweet chocolate lie somewhere in the middle. As a safety measure, it should not be given to your cat or any pet under any circumstances. Caffeine in large enough quantities can be fatal for a cat. And there is no antidote. Symptoms of caffeine poisoning include restlessness, rapid breathing, heart palpitations, muscle tremors, and fits. In addition to tea and coffee — including beans and grounds — caffeine can be found in cocoa, chocolate, colas, and stimulant drinks such as Red Bull. It’s also in some cold medicines and painkillers.http://www.petplace.com/article/cats/diseases-conditions-of-cats/features/dangerous-foods-are-they-harmful-to-your-cathttp://pets.webmd.com/cats/ss/slideshow-foods-your-cat-should-never-eat

Cooked Bones from fish, poultry, or other meat sources can cause obstruction or laceration of the digestive system if the pieces are too large. For cats, a chicken neck or wing bone fed raw is safe and even encouraged by some raw food advocates. Cooking bones greatly reduces their benefits and poses many dangers rendering the natural calcium almost unavailable for absorption. Cooked bones are much tougher and more brittle than raw bones, and will actually blunt an animals teeth after regular chewing. They also break into large chunks more easily, and your pet may swallow a piece too large to digest. Cooked bones are very slow to breakdown in the animals gut and can cause severe gut pain (colic), scarring of the gut lining and bleeding, which can lead to constipation.http://www.cat-world.com.au/human-foods-which-are-poisonous-to-cats

Nuts of any kind are harmful but Walnuts and their hulls and Macadamia Nuts are especially toxic. Effects can be anything from vomiting and paralysis to death. Pets can start to develop symptoms such as an inability to stand or walk, vomiting, hyperthermia (elevated body temperature), weakness, and an elevated heart rate within 12 hours of eating nuts. Nuts of any kind are high in fat and can cause inflammation of the pancreas (pancreatitis) and their high phosphorous levels can possibly lead to bladder stones. Walnuts and most nuts can develop a fungus called alfatoxin. It can cause gastrointestinal problems such as vomiting and diarrhea, as well as respiratory issues such as sneezing, breathing and coughing. Aflatoxins – a naturally occurring fungus on grains and legumes – is a carcinogenic fungus. Avoid all animal-feed grade nuts.http://www.peteducation.com/article.cfm?c=2+1677&aid=2411http://ottawavalleydogwhisperer.blogspot.com/2012/02/foods-that-dogs-should-never-eat.html

Raisins and Grapes can cause kidney failure in some dogs, but not all dogs are susceptible to the toxic effects of these foods. Some dogs have died after eating a few grapes while it doesn’t seem to bother others. There have only been occasional reports of cats developing problems after eating raisins and it’s not yet known why the fruits may be toxic. It’s unknown if it is a mycotoxin (produced by a fungus), pesticide, heavy metal, or a yet-unidentified toxin.

Raw Eggs whites contain an enzyme called avidin, that decreases the absorption of biotin (a B vitamin) and can lead to skin and hair coat problems. Cooking the egg whites neutralizes the avidin, therefore raw egg yolks are safe to feed when feeding a raw diet, whereas raw egg whites are not.http://pets.thenest.com/raw-egg-whites-good-cats-dogs-6763.html

Spinach does not belong in pet food! Spinach has one of the highest calcium oxalate levels of any food. Cooking does NOT diminish the oxalates much at all, very minimally. The oxalates in spinach are very sturdy, binding and are around 600-750 content milligrams per 100 gram serving. You’d have to boil or blanch it to reduce it even 5-15% and then you’ve lost all the nutrients in it. 1/2 a cup of cooked spinach contains 755 mgs of oxalates and 1 cup of raw spinach contains 656 mgs. Because spinach is now being added in a lot of pet food brands, you may want to make sure to feed other foods and rotate that food so it’s not fed every day. Or if your cat suffers from kidney, gallbladder or thyroid issues, you should forgo feeding it to them altogether! They should not be eating any foods with those levels as it can do severe damage. Spinach can cause crystal formation in the urinary tract and kidneys in cats. Calcium oxalate stones are EXTREMELY painful and once formed in the kidneys, cannot be removed. Whether cooked or raw, spinach should be completely avoided in cats and has been shown to cause such major damage it can result in hospitalization and in some circumstances, death. I personally know someone who’s cat died from being fed raw spinach. I recommend writing to the pet food companies that do include spinach and request that they remove it completely from their products. NEVER feed raw spinach to your pet, whether they are ill or healthy!

Spoiled Food, Mold and Bacteria: Spoiled foods and molds that grow on food harbor harmful bacteria and may also contain toxins. Unless starving, cats will generally avoid stale or spoiled foods. If they do ingest it, their first line of defense is to vomit it back up again. If the food smells or looks bad to you, throw it out. Don’t feed it to your cat or yourself. (I really don’t think I need to include a link for this one, I’d hope people would have common sense to know this is true).

Sweeteners: Sorbitol falls within the same chemical category as the sweeteners xylitol and mannitol. Because it’s especially hard for them to digest, large amounts of sorbitol can affect pets in an adverse way. Sorbitol is used in a multitude of pet foods for moisture retention, is less vulnerable to mold and may be bacteria resistant. It is also used as a plastic making agent. Sorbitol and mannitol for a pet can lead to severe diarrhea, GI irritation and malabsorption issues. Although not toxic like xylitol, sorbitol used in anything other than pet food may be best avoided, especially with cats already experiencing GI upset like an IBD kitty, or one with a compromised immune system. Most pet toothpaste brands contain up to 50% sorbitol and states clearly on their literature that it can give them very bad stomach upset and diarrhea; which is what happened to my cats.

Like tomatoes, Potatoes are members of the solanaceae family of plants and are also related to deadly nightshade. They also contain glycoalkaloid solanine and any uncooked or green potatoes and potato peelings are all toxic. Once cooked, the alkaloid is destroyed making the potato safe.

Yeast/Bread Dough – Bread dough can quickly expand in a cat’s stomach, causing it to swell beyond its capacity, cutting off its blood supply. The expanding dough can produce gas in the digestive system, causing pain and possible rupture of the stomach or intestines. Also, ethanol produced by the fermenting yeast is absorbed into the blood stream causing effects such as being uncoordinated and disorientation. Brewer’s yeast and dried yeast can cause a whole host of other problems such as allergies, skin conditions, GI irritation, etc.http://pets.webmd.com/cats/ss/slideshow-foods-your-cat-should-never-eat#

Xylitol, a common sweetener found in some diet products, chewing gum, candy, etc., may cause a sudden drop in an animal’s blood sugar, loss of coordination and seizures. Xylitol has been linked to liver failure in dogs and death within hours of ingestion. According to the American Society for the Prevention of Cruelty to Animals, xylitol is toxic to animals. In cats it can prompt a sudden release of insulin, resulting in low blood sugar, a condition known as hypoglycemia. Signs that your cat may have swallowed a product containing xylitol include a sudden lack of coordination, vomiting, lethargy and, eventually, seizures and possibly coma. Ultimately a cat that eats xylitol may end up with liver failure, resulting in death.http://pets.thenest.com/xylitol-harmful-cats-4576.html